Resin treatment of wool fabric



Pat ented Mar. 20, 1951 v TENT OFFICE RESIN TREATMENT WOOL FABRIC John N. Dalton and William B. Kaupin, Lawrence, Mass, assignors to Pacific Mills, Lawrence, Mass., a corporation of Massachusetts No Drawing. Application February 18, 1948, Serial No. 9,846

A 6 Claims.

1 The present invention relates to the treatment of wool or part wool textile fabrics and to the resulting textile fabrics. An objectis to produce such a fabric retaining substantially th soft hand, tensile strength and resistance to wear of the fabric before treatment and with a durable resistance to shrinkage when laundered. An-

In the practice of our invention we impregnate.

and swell a wool, or part wool, textile fabric with an aqueous solution or dispersion of certain resinfo-rming materials and an acid catalyst, and, after squeezing out excess liquid, we heat the wet fabric throughout from surface to surface homogeneously and so rapidly that the resin-forming materials on the wool practically instantaneously become so viscous that they have no time to migrate appreciably and do not so migrate and the resin distribution remains in effect homogeneous throughout the fabric from surface to surface. This we carry out by infra-red or radio frequency radiation by which we accomplish this homogeneous practically instantaneous heating of .the wet fabric atbetween 140 and about 212 F. "We thereby prohibit the concentration of resin at or near the surfaces of the fabric which we have found to be a cause of the harsh finish of wool fabrics as previously treated with resin and we obtain a resin treated fabric which is homogeneous from surface to surface.

softness of the fabric and the resin contained therein.

The finished fabric has the softness, flexibility,

tensile strength and wear resistance of the untreated fabric and has the desired improvement in dimensional stability, i. e., resistance to shrinkage on repeated laundering. It has an enhanced fixation of acid dyes.

The resin-forming materials in the impregnating bath may be either in the monomeric state or may be partially condensed to a lowmolecular-weight reaction product which is capable of being dissolved or dispersed in water. By solution as used herein we include such dispersions. The resin-forming materials which we employ are the methylolmelamines including the alkylated methylolmelamines' and preferably in addition thereto urea, thiourea, hydroxylamine, guanidine or other amines. When the bath contains an amine it may also contain formaldehyde or a formaldehyde-liberating substance. Particularly good results are obtained with urea and methylated methylolmelamine. The resin concentration in the bath and the amount of liquid taken up by the fabric are so regulated as to incorporate in the fabric 5 to 10% of resin solids by weight of the fabric. The urea combines with the formaldehyde in the bath and with that liberated by the methylolmelamine during the heating of the fabric. In the finished fabric the resin-forming materials are polymerized and combined with the wool.

The following is a process typical of our invention. A light wool fabric was acid dyed with 3% Alizarin Blue SE, Color Index 1053, by a conventional method, and the final rinse adjusted so that the fabric retained about 3% sulfuric acid on the weight of the fabric, as the catalyst for the resin-forming reaction. After being dyed; the fabric was continuously processed at a speed of about 15 yards per minute. It was padded in an impregnating bath containing 6% methylated methylolmelami'ne solids, 2% urea and 2% alpha trioxymethylene (a source of formaldehyde), by weight of the bath, with a total immersion time of about 10 seconds. The fabric on leaving the bath was squeezed to remove so much of the impregnating solution as to leave in the fabric an amount of the solution equal to about of the dry weight of the fabric. The wet fabric was heated homogeneously throughout from surface to surface by being subjected to the rays of infrared lamps by which the temperature of the fabric was raised to about F. while retaining about one-third of its water content. The resin-forming materials were changed to a viscous condition so instantly that they did not migrate to the surfaces of the fabric but remained homogeneously throughout the fabric.

The fabric, as it advanced, was heated on a tenter and then subjected to the rays of infrared' lamps by which its temperature was raised to about 300 F. The methylated methylolmelamine, ureaand formaldehyde were polymerized. and combined with the. wool.

The treated fabric had the same softness, flexibility (hand and feel) and tensile strength as the fabric before treatment. It had no appreciable surface resin which in many treated wool' fabrics causes stiffness or a .boardy' handle, but

the resinous materials were-homogeneous from.

surface to surface of the fabric.

Samples of the treated fabric and similarly dyed, but otherwise untreated, control samples."

were subjected to standard wool washing tests (CC-T191a, Fed. Spec. for Textiles, Sec. 'IV, part 5, Par. XIV) and to standard perspiration tests. The treated specimens werezfound to retain fabric character and. dimensional stability after .re-

after five launderings- The treated samples were given astandard alkaline perspiration test and were-not altered in shade and did not produce any bleeding on the white test cloth. The controls, however, became streaky, changed in shade and bled badlyonto the test cloth.

The tensile strengths of both warp and filling of the treated samples were as good as those of the controls in all cases and in some specimens they. were i noticeably better.

In ounrprocess the urea, or its equivalent, and the: methylolmelamine and formaldehyde are polymerized andcombined with the wool. Sufficient urea may be included in the impregnating bath to. react with all of the formaldehyde liber--- ated from the methylolmelamine during the resin-forming reaction. We may add larger amounts of urea, up to about of the weight of the-methylolmelamin'e, andin this case thebath shouldinclude an amount of formaldehyde, or a formaldehyde-liberating substance, sufficient to provide autotal of. l to 2. mols of formaldehyde for each mol of urea. at the timeof reaction.

Weprefer to providethecatalyst as residual acid :01. acid salt'remaining: in the fabric from.

the'idyeing'operationor supplied by padding with such acid and may use for this purpose inorganic acids such assulfuric, .hydrochlori or phosphoric.

or organic acids such as formic, tartari 'maleic or itaconic .or their salts. These ways of introducing the catalyst avoid thenecessity of includ.-

ing a catalyst as an ingredient in the impregnating bath.- The acid should be present. in the fabrimwhenit isheated, in an amount suificient' toprovide a pH of about2 to 5.

The resin treated wool fabrics disclosed herein are disclosedandc-laimed in my continuation-inpart application Serial No; 194,942 filed November'9,-1950.-

We claim:

' 1. The method of treating a wool fabric to en-" hance its dimensional stability under laundering conditions while preserving its properties of fieX- ibility, tensile strength and soft hand and feel substantially equal to those of the untreated fabric, which comprises impregnating the fabric with an aqueous solution of 5% to 10% of the weight of the fabric of. resin-forming materials comprising'a methylolmelamine :andi formaldehyde, exposing the wet impregnated fabric to infra-red radiation to heat it substantially uniformly fromsurface to surface and immediately raise its temperature to F. to 212 F. so that sufficient wateris. almost instantly driven off to leave about'one-third of the original water content, thus-converting said resin-forming materials to a viscous condition while said solution is maintained uniformly distributed through the whole thickness of the fabric, whereby said materials are. immobilized therein against migration to the surfaces of the fabric, and thereafter polymerizing .said'resineforming materials to waterinsoluble condition. by further heating the fabricto a temperature of:212- F. to 309 F.

2. The method of treating a wool fabricsto enhance its dimensional stability under laundering'.-conditions while preserving its properties :of flexibility, tensile strength-andsoft hand and feelsubstantially' equal to those of the 'untreated fabric, which comprises. impregnating the fabric with an aqueous solution of 5.%=to 10%.of the weight-10f the fabric of resin-formingimaterials comp-rising a methy-lolmelamine .andformaldehyde, exposing thexwet impregnated. fabric to infra+redi radiation to heat; it substantially .uni-' formly; from 'SllIfEtCfi-tO surface-and immediatelyraise. its temperaturezzto 180 to 212 F. so, that. sufficient water is almost. instantly; driven off to. leave about one-third of the original Water con-- tent, thus converting: said; resin-forming :materials toa .viscouslcondition whilesa-id solution is maintained uniformlyr distributed through the whole thicknessof the. fabric, :whereby .said. materi als area-immobilized. therein.againstmigration to the surfaces of. the-ifa'bric and thereafter polymerizingsaid n'esin-forming.materialsazto water-:1 insoluble conditionby further'heating .the' fabricto a temperatureof-t 212 to.30O F:

3. The method of. treating. a wool fabric=to1 en-x' hance its .dimensional'stability. .under filaundering conditions while preserving its properties of flex-w ibility, tensile strength and soft hand and feel substantially equal'to. those of theluntreated fab-- ric, which :comprises':impregnating' the. fabric. with an aqueousisolutionrof 5% to 10% of the. weight of the fabric of resineforming materials comprising an alkylated: Inethylolmelamine and formaldehyde, exposing the wet. impregnatedfaba ric to infra-eredi'radiatiomto heat; itsubstantially uniformly from surfaceto surface and immediately raise its tempearture'zto 1409 1 to 212 :F. so that suf icient-water.'iszalmost clnstantlydriven off to leave aboritone-third of the original .water content, thus convertingsaid resinefor-ming terialstoa viscous condition: while saidsolution is maintained uniformly distributed :throughst'n whole. thickness ofthe fabricpwhereby saidmat'e rials are: immobilizedd therein against-migration to the surfaces of. the fabric and. thereafter polymerizing sa'id resin-forming mater-ialstto waterinsoluble condition by furtherheatingthe fabric" to a temperature of 212* to 300 E.

4. The methodof treating awool fabric toenhance: its dimensional stability under laundering conditions'while preserving its properties of' flexibility, tensile strength and soft hand and -fe'elsubstantially equal to those of the untreated fabric, which comprises impregnating the fabric with an aqueous solution of 5% to of the weight of the fabric of resin-forming materials comprising an alkylated methylolmelamine, urea and formaldehyde, exposing the wet impregnated fabric to infra-red radiation to heat it substantially uniformly from surface to surface and immedi ately raise its temperature to 140 F. to 212 so that sufficient water is almost instantly driven off to leave about one-third of the original water content, thus converting said resin-forming materials to a viscous condition while said solution is maintained uniformly distributed through the whole thickness of the fabric, whereby said ma terials are immobilized therein against migration to the surfaces of the fabric and thereafter polymerizing said resin-forming materials to water-insoluble condition by further heating the fabric to a temperature of 212 to 300 F.

5. The method of treating a wool fabric to enhance its dimensional stability under laundering conditions while preserving its properties of flexibility, tensile strength and soft hand and feel substantially equal to those of the untreated fabric, which comprises impregnating the fabric with an aqueous solution of 5% to 10% of the weigh of the fabric of resin-forming materials comprising a methylated methylolmelamine, urea and formaldehyde, exposing the wet impregnated fabric to infra-red radiation to heat it substantially uniformly from surface to surface and immediately raise its temperature to 140 F. to 212 F. so that sufficient Water is almost instantly driven off to leave about one-third of the original water content, thus converting said resin-forming materials to a viscous condition while said solution is maintained uniformly distributed through the whole thickness of the fabric, whereby said materials are immobilizedtherein against migration to the surfaces of the fabric and thereafter polymerizing said resin-forming materials to water- 6 insoluble condition by further heating the fabric to a temperature of 212 F. to 300 F.

6. The method of treating a wool fabric to enhance its dimensional stability under laundering conditions while preserving its properties of flexibility, tensile strength and soft hand and feel substantially equal to those of the untreated fabric, which comprises impregnating the fabric with an aqueous solution of 5% to 10% of the weight of the fabric of resin-forming materials comprising a methylated methylolmelamine, urea and formaldehyde, exposing the wet impregnated fabric to infra-red radiation to heat it substantially uniformly from surface to surface, and immediately raise its temperature to 180 F. to 212 F. so that sufficient water is almost instantly driven off to leave about one-third of the original water content, thus converting said resinforming materials to a viscous condition while said solution is maintained uniformly distributed through the whole thickness of the fabric, whereby said materials are immobilized therein against migration to the surfaces of the fabric, and thereafter polymerizing said resin-forming materials to water-insoluble condition by further heating the fabric to a temperature of 212 F. to 300 F.

JOHN N. DALTON. WILLIAM B. KAUPIN.

. REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 22,566 Johnstone et a1 Nov. 21, 1944 1,470,990 Lucas Oct. 16, 1923 1,845,322 Neuhauss Feb. 16, 1932. 2,121,006 Bener June 21, 1938 2,190,672 Meharg Feb. 20, 1940 2,248,696 Cassel July 8, 1941 2,321,938 Quinn June 15, 1943 

1. THE METHOD OF TREATING A WOOL FABRIC TO ENHANCE ITS DIMENSIONAL STABILITY UNDER LAUNDERING CONDITIONS WHILE PRESERVING ITS PROPERTIES OF FLEXIBILITY, TENSILE STRENGTH AND SOFT HAND AND FEEL SUBSTANTIALLY EQUAL TO THOSE OF THE UNTREATED FABRIC, WHICH COMPRISES IMPREGNATING THE FABRIC WITH AN AQUEOUS SOLUTION OF 5% TO 10% OF THE WEIGHT OF THE FABRIC OF RESIN-FORMING MATERIALS COMPRISING A METHYLOLMELAMINE AND FORMALDEHYDE, EXPOSING THE WET IMPREGNATED FABRIC TO INFRA-RED RADIATION TO HEAT IT SUBSTANTIALLY UNIFORMLY FROM SURFACE TO SURFACE AND IMMEDIATELY RAISE ITS TEMPERATURE TO 140* F. TO 212* F. SO THAT SUFFICIENT WATER IS ALMOST INSTANTLY DRIVEN OFF TO LEAVE ABOUT ONE-THIRD OF THE ORIGINAL WATER CONTENT, THUS CONVERTING SAID RESIN-FORMING MATERIALS TO A VISCOUS CONDITION WHILE SAID SOLUTION IS MAINTAINED UNIFORMLY DISTRIBUTED THROUGH THE WHOLE THICKNESS OF THE FABRIC, WHEREBY SAID MATERIALS ARE IMMOBILIZED THEREIN AGAINST MIGRATION TO THE SURFACES OF THE FABRIC, AND THEREAFTER POLYMERIZING SAID RESIN-FORMING MATERIALS TO WATERINSOLUBLE CONDITION BY FURTHER HEATING THE FABRIC TO A TEMPERATURE OF 212* F. TO 300*. 